On May 08, 2007 09:32 -0600, Nadolski, Ed wrote: > - Do the Lustre modules on the OSS all run entirely in kernel mode?
Yes. > Is there anything in the IO path that invokes a user/kernel transition, or > perform any data block copying? For regular userspace IO there is always a copy between userspace and kernel. If you use TCP then there is another copy on receive (either on the client or server depending on whether you are reading or writing). > - Where do the Lustre modules hook into the back-end IO stack on the > OSS? (VFS/VOP? Block? SCSI? submit_bio()?) I'm interested in > optimizing the Linux IO stack but I don't want to collide with any > Lustre changes. The majority of filesystem operations are done at the VFS/VOP level. For bulk data IO (read/write) they use submit_bio() (see filter_io_26.c). > - Does Lustre on the OSS make use of the Linux page cache or direct IO? > Is any of that configurable? Not currently. > - What Linux kernel goes with Lustre 1.6? Depends which distro you are using. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. _______________________________________________ Lustre-discuss mailing list [email protected] https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
